Dunno, but I think online orders ship more or less directly from the factory and I'd think that gives them a very high chance of being the latest revision.
Yes, ordering directly with a custom config - in particular, one other than RAM changes - will help ensure you get the latest and greatest. But... odds are very good that, by the time yours arrives, even more fixes are in the pipe. Just buy one already.
When ordering over the phone also be sure to get the name/employee number of whoever is answering your call, or if you are ordering through a local shop likewise get the employee to write down your request (ie: customer requested to have a latest revision Macbook Pro 2.0Ghz, signed loyal Apple employee) and make him initial on it.
Otherwise it will be nothing more than a "Sure... you will get the very latest Macbook Pro, rest assured!" and moments later after you left, "Hey Jim! Grab one Macbook Pro for this guy, I will send you his particulars"